1. Field of the Invention
The present invention relates to metal sheet members and more particularly, to a metal sheet member having high plastic bonding strength for the bonding of a plastic material.
2. Description of the Related Art
Following fast development of electronic industry, many advanced mobile electronic products (such as: intelligent cell phone, notebook, PDA, and etc.) are created having light, thin, short and small characteristics convenient for carrying. In order to reduce the weight while maintaining the advantages of metal appearance, a plastic member may be used with a metal sheet member for making a housing. The metal sheet member protects the product and facilitates coating. Conventionally, adhesive is usually used for the bonding between a metal sheet member and a plastic member. This method has drawbacks as follows:
1. When the adhesive is hardened, the volume of the adhesive will be reduced (fluid of the adhesive changed into vapor), causing gaps between the metal sheet member and the plastic member and lowering the yield rate.
2. Because the metal sheet member and the plastic member have different coefficients of thermal expansion, the metal sheet member may drop from the plastic member due to sharp temperature change. When an electronic product is distributing in different countries of different climate zones, metal sheet member disconnection problem may occur frequently.
3. When using an adhesive to bond a metal sheet member to a plastic member, it wastes much waiting time for the hardening of the adhesive, thereby prolonging the fabrication time. Further, the use of an adhesive greatly increases the cost of the electronic product, causing consumers not willing to buy the product.